A graduate of an Alabama high school was among five Army soldiers killed in a helicopter crash Friday over the Mediterranean Sea during a training exercise, according to the military and his former assistant principal.

Chief Warrant Officer 3 Stephen R. Dwyer, 38, of Clarksville, Tennessee, graduated from Enterprise High School in 2004, said Enterprise Mayor William E. Cooper, who knew Dwyer from the high school.

“We are heartbroken to learn that Steve was killed while in service to our country,” Cooper said in a statement on the city’s Facebook page. “I was Assistant Principal when he was in high school, and I remember him fondly. Let’s all lift up his wife, their three boys, his parents, sister and other family members and friends in prayer as they go through this unimaginable time.”

Dwyer was among five U.S. Army Special Operations soldiers killed in the crash of the MH-60 Blackhawk, which was conducting aerial refueling training when it encountered an in-flight emergency resulting in the accident, according to the Department of Defense.

“Our thoughts and prayers remain with the families of the fallen,” the agency said. “The U.S. Army’s Combat Readiness Center is conducting an investigation into the incident.”

Also killed in the crash were:

• Chief Warrant Officer 2 Shane M. Barnes, 34, of Sacramento, California
• Staff Sgt. Tanner W. Grone, 26, of Gorham, New Hampshire
• Sgt. Andrew P. Southard, 27, of Apache Junction, Arizona
• Sgt. Cade M. Wolfe, 24, of Mankato, Minnesota.

“May their family and friends find comfort in the fact that these men were serving and defending their country, providing a fine example for all of us of true patriotism. May God Bless their souls,” Cooper said.

Lt. Gen. Jonathan P. Braga, commanding general of U.S. Army Special Operations Command, said the soldiers were “incredible teammates.

“We mourn the loss of these five incredible soldiers, each of them a national treasure. They hail from rare patriotic families with deep military service ties that span multiple generations and formations,” he said.

“This is devastating news that reverberates across the entire special operations community. Every loss is tough, but in this case, service to the Nation is truly a family business and it’s hard to express the amount of sorrow that we all feel right now,” Braga continued.

“Our thoughts and prayers are with their families, their loved ones, and their fellow soldiers,” he said. “Like the special operations community always does, we will wrap our arms around them, grieve with them, and promise to never forget them.”